Consent

Commercial Use Data RestrictionsNo

Data Restrictions Based On Area Of ResearchNo

Specific Consent Restrictions
None

Available Data

Data available for request include the STICH main study data and the STICHES ancillary study data, which extended the follow-up of surviving subjects randomized in the STICH trial myocardial revascularization hypothesis (Hypothesis 1) for an additional 5 years.

Objectives

Background

Coronary artery disease (CAD) is the most common cause of heart failure, which in turn is a major cause of death and disability globally. Evidence from previous clinical trials supports the use of coronary-artery bypass grafting (CABG) to relieve disabling symptoms of angina, particularly among high-risk subgroups with extensive CAD. However, the studies did not include patients with severe left ventricular dysfunction, and developments in medical therapy have since led to updated guidelines. In addition, the benefits of CABG in patients with ischemic cardiomyopathy had still not been clearly established at the time of this study. STICH sought to evaluate the role of CABG in the treatment of patients with CAD and left ventricular systolic dysfunction.

Reduced left ventricular function may occur after myocardial infarction, often in conjunction with left ventricular remodeling, including left ventricular enlargement and changes in chamber geometry. Left ventricular remodeling is correlated with progression of heart failure and a poor prognosis. Therefore, a surgical approach to remodeling through left ventricular volume reduction could improve outcomes for patients with CAD and heart failure. Surgical ventricular reconstruction (SVR) has been shown to reduce the left ventricular volume, increase the ejection fraction, and improve ventricular function. There is also evidence that SVR performed with CABG may reduce the rate of hospitalization and improve ventricular function, as compared to CABG alone. As part of a second hypothesis, STICH additionally investigated whether SVR when added to CABG would improve outcomes in patients with heart failure and CAD.

Subjects

Eligible patients were at least 18 years of age, had CAD that was amenable to CABG, and an ejection fraction of 35% or less. Exclusion criteria included recent myocardial infarction, a need for aortic-valve replacement, a planned percutaneous coronary intervention, or non-cardiac disease with less than three years life expectancy. Patients with at least 50% stenosis of the left main coronary artery, or that had angina of CCS class III or IV while receiving medical therapy were not eligible for medical therapy alone. Patients who were found to have dominant anterior akinesia or dyskinesia of the left ventricle were eligible for SVR.

A total of 2,136 patients were enrolled in STICH. 1,212 were enrolled in the hypothesis 1 component of the trial with 602 participants assigned to receive medical therapy alone, and 610 participants assigned to receive medical therapy plus CABG. 1,000 were enrolled in the hypothesis 2 component with 499 participants assigned to receive medical therapy plus CABG, and 501 participants assigned to receive medical therapy plus CABG and SVR. 76 participants that were assigned to the CABG with medical therapy treatment were enrolled in both hypothesis components.

Design

After initial determination of overall eligibility, patients were evaluated to determine which component of the STICH program was appropriate for them on the basis of suitable therapeutic options. All patients underwent cardiac imaging for assessment of left ventricular function and wall motion. Participants in the hypothesis 1 component were randomly assigned to receive either medical therapy alone or medical therapy plus CABG. Participants in the hypothesis 2 component were randomly assigned to receive either medical therapy plus CABG or medical therapy plus CABG and SVR.

At baseline, demographic factors and clinical characteristics were assessed, including current medications and prior diagnostic and other cardiovascular procedures, and a physical examination was performed. Guideline-based recommendations for drug and device use were emphasized for all patients. All patients underwent follow-up evaluations at the time of discharge or at 30 days for patients still hospitalized, every 4 months for the first year, and every 6 months thereafter. The median length of follow-up was 56 months for hypothesis 1 and 48 months for hypothesis 2.

For patients receiving CABG, arterial grafting for stenosis of the left anterior descending coronary artery was required for all patients without specific contraindications. The use of additional arterial conduits supplemented by vein grafts was recommended for revascularization of all major vessels with clinically significant stenoses. Concurrent mitral-valve surgery for regurgitation was performed at the discretion of the surgeon. For patients receiving SVR, the operation was most commonly performed during a single period of cardioplegic arrest after construction of bypass grafts. However, the procedure could also be performed with the heart beating in order to facilitate identification of the noncontractile zone of scarring. After an anterior left ventriculotomy was centered in the zone of anterior asynergy, a suture was placed in the interior of the ventricle to encircle the scar at the boundary between the akinetic and viable tissue. Visual inspection and palpation facilitated the judgment of whether a patch was needed to optimize the chamber size without deforming the left ventricle during closure of the ventriculotomy.

The primary outcome for hypothesis 1 was the rate of death from any cause. The primary outcome for hypothesis two was a composite of death from any cause and hospitalization for cardiac causes.

Conclusions

There was no significant difference between medical therapy alone and medical therapy plus CABG for death from any cause, though patients that underwent CABG had lower rates of death from cardiovascular causes, death from any cause, or hospitalization for cardiovascular causes. Adding SVR to CABG reduced the left ventricular volume, as compared with CABG alone. However, this anatomical change was not associated with a greater improvement in symptoms or exercise tolerance, or with a reduction in the rate of death or hospitalization for cardiac causes.

Study Documents

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